<h2>
Hello!</h2>
The answer is:

<h2>
Why?</h2>
To solve the problem we need to add/subtract like terms. We need to remember that like terms are the terms that share the same variable and the same exponent.
For example, we have:

We have that we were able to add just the terms that were sharing the same variable and exponenr (x for this case).
So, we are given the expression:

Hence, the answer is:

Have a nice day!
I can not see the image sorry!!!
Answer:f=99
Step-by-step explanation
solve for f by simplifying both sides of the equation, then isolating the variable.
We are given the quadratic:

, with a=1, b=-8, c=15.
We know that the x-coordinate of the vertex, which is the point where the line of symmetry passes through is

.
Thus, the x-coordinate of the vertex is

.
Thus, the line of symmetry is x=4.
Answer: <span>B. The line of symmetry should have been 4 instead of –4. </span>